A serious problem exists in coal storage at power plants. Rainwater penetrates into coal, increasing its moisture content, washing out coal dust which runs into streams and lakes, causing fish kills and other environmental problems. Numerous methods have been proposed to correct this problem, such as films and rigid coated celled foams. These measures are inadequate and do not prevent rainwater infiltration, due to the fact that neither films nor spray on foams can be put down without openings which allow the penetration of water.
Similarly, various other particulate solid commodities such as lignite, limestone, various forms of wood, tailings from mining operations and grains such as corn, wheat, barley and oats, all which are often stored outdoors in piles whereby they are exposed to the weather elements such as rain and melting snow, are adversely affected by such exposure.